Flat head machine screws are conical with a flat outer face and a tapering inner face of 80 Deg to 82 Deg. Flat heads lay flush with the mating surface and very little protrudes above for a smooth appearance. Machine screws are used with nuts or screwed directly into a tapped hole to fasten components together. Slotted flat head screws use standard blade screwdrivers. Length of flat head machine screws are measured from the top of the head to the point of the screw.Kit contains the following 330-pieces of slotted flat head machine screws: 6-32 x 3/8 in. 25-pieces 6-32 x 1/2 in. 25-pieces 6-32 x 3/4 in. 25-pieces 8-32 x 3/8 in. 25-pieces 8-32 x 1/2 in. 25-pieces 8-32 x 3/4 in. 25-pieces 10-24 x 1/2 in. 20-pieces 10-24 x 3/4 in. 20-pieces 10-24 x 1 in. 20-pieces 12-24 x 1/2 in. 10-pieces 12-24 x 3/4 in. 10-pieces 12-24 x 1 in. 10-pieces 1/4-20 x 1/2 in. 10-pieces 1/4-20 x 3/4 in. 10-pieces 1/4-20 x 1 in. 10-pieces 10-32 x 1/2 in. 20-pieces 10-32 x 3/4 in. 20-pieces 10-32 x 1 in. 20-piecesMaterial: steel zinc platedUse standard blade screwdriverClear plastic carrying case for easy storagePair with corresponding nut and washer in like finishesCommon project applications: electronics, license plates, electrical boxes, switch plates, furniture